btrfs: add forward declarations and headers, part 1

Do a cleanup in the short headers:

- add forward declarations for types referenced by pointers
- add includes when types need them

This fixes potential compilation problems if the headers are reordered
or the missing includes are not provided indirectly.

Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: zoned: support RAID0/1/10 on top of raid stripe tree

When we have a raid-stripe-tree, we can do RAID0/1/10 on zoned devices
for data block groups. For metadata block groups, we don't actually
need anything special, as all metadata I/O is protected by the
btrfs_zoned_meta_io_lock() already.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: lookup physical address from stripe extent

Lookup the physical address from the raid stripe tree when a read on an
RAID volume formatted with the raid stripe tree was attempted.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: delete stripe extent on extent deletion

As each stripe extent is tied to an extent item, delete the stripe extent
once the corresponding extent item is deleted.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

btrfs: add support for inserting raid stripe extents

Add support for inserting stripe extents into the raid stripe tree on
completion of every write that needs an extra logical-to-physical
translation when using RAID.

Inserting the stripe extents happens after the data I/O has completed,
this is done to

a) support zone-append and
b) rule out the possibility of a RAID-write-hole.

Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>